Velentina Boulter
Velentina Boulter is an intern at Cosmos as part of her Master of Journalism at the University of Melbourne.
Recent research from the Marine Biological Laboratory at the University of Chicago, has uncovered an unusual form of cell division in one of the most common forms of bacteria – those that live in dental plaque.
The researchers observed Corynebacterium matruchotii which produces precipitate calcium phosphate in the mouth, undergo a division process known as “multiple fission.”
For bacteria, the most common form of cell division involves the parent cell splitting into two daughter cells. However, with multiple fission, the parent cell divides into several daughter cells instantaneously.
Published in the Proceedings of the National Academy of Sciences, the research team observed the plaque bacteria cells divide into as many as 14 cells at once, which helps to explain why C. matruchotii can grow rapidly within dental plaque.
“Something about this very dense, competitive habitat of the dental plaque may have driven the evolution of this way of growing,” said Dr Scott Chimileski, lead author of the study.
The study also found that the bacteria can grow up to half a millimetre per day, so even the most meticulous teeth brushers would struggle to eliminate the bacteria completely.
“Who would have thought that our mouths would harbour a microbe whose reproductive strategy is virtually unique in the bacterial world,” says former head of the Marine Biology Lab and co-author Gary Borisy.
“The next challenge is to understand the meaning of this strategy for the health of our mouths and our bodies.”
Interestingly, the cells only grew off one pole of the mother cell, which is known as tip extension. The structural proteins of these cells, or filaments, then act as a foundation for other bacteria to live in.
“Reefs have coral, forests have trees, and the dental plaque in our mouths has Corynebacterium. The Corynebacterium cells in dental plaque are like a big, bushy tree in the forest; they create a spatial structure that provides the habitat for many other species of bacteria around them,” says the paper’s co-author Jessica Mark Welch.
Other dental advice
Inside your mouth, there are currently more than 700 different species of bacteria. They live in biofilms – communities of microorganisms that stick to each other and an external surface.
“These biofilms are like microscopic rainforests,” says Chimileski. “The bacteria in these biofilms interact as they grow and divide. We think that the unusual C. matruchotii cell cycle enables this species to form these very dense networks at the core of the biofilm.”.
“To figure out how all the different kinds of bacteria work together in the plaque biofilm, we have to understand the basic biology of these bacteria, which live nowhere else but the human mouth,” said Mark Welch.
There are other species of the Corynebacterium that can be found inside nasal cavities and on the skin.
